基因组不稳定性
乙型肝炎病毒
同源重组
生物
突变体
分子生物学
DNA修复
增殖细胞核抗原
病毒学
DNA
DNA损伤
癌症研究
化学
病毒
基因
遗传学
作者
Yi‐Hsuan Hsieh,Yu‐Ying Chang,Ih‐Jen Su,Chia‐Jui Yen,Yiru Liu,Ren‐Jei Liu,Wen‐Chuan Hsieh,Hung‐Wen Tsai,Lily Wang,Wenya Huang
摘要
Abstract Although hepatitis B virus ( HBV ) has been established to cause hepatocellular carcinoma ( HCC ), the exact mechanism remains to be clarified. Type II ground glass hepatocytes ( GGHs ) harbouring the HBV pre‐ S 2 mutant large surface protein ( LHBS ) have been recognized as a morphologically distinct hallmark of HCC in the advanced stages of chronic HBV infection. Considering its preneoplastic nature, we hypothesized that type II GGH may exhibit high genomic instability, which is important for the carcinogenic process in chronic HBV carriers. In this study we found that pre‐ S 2 mutant LHBS directly interacted with importin α1, the key factor that recognizes cargos undergoing nuclear transportation mediated by the importin α/β‐associated nuclear pore complex ( NPC ). By interacting with importin α1, which inhibits its function as an NPC factor, pre‐ S 2 mutant LHBS blocked nuclear transport of an essential DNA repair and recombination factor, Nijmegen breakage syndrome 1 ( NBS1 ), upon DNA damage, thereby delaying the formation of nuclear foci at the sites of DNA double‐strand breaks ( DSBs ). Pre‐ S 2 mutant LHBS was also found to block NBS1 ‐mediated homologous recombination repair and induce multi‐nucleation of cells. In addition, pre‐ S 2 mutant LHBS transgenic mice showed genomic instability, indicated by increased global gene copy number variations ( CNVs ), which were significantly higher than those in hepatitis B virus X mice, indicating that pre‐ S 2 mutant LHBS is the major viral oncoprotein inducing genomic instability in HBV ‐infected hepatocytes. Consistently, the human type II GGHs in HCC patients exhibited increased DNA DSBs representing significant genomic instability. In conclusion, type II GGHs harbouring HBV pre‐ S 2 mutant oncoprotein represent a high‐risk marker for the loss of genome integrity in chronic HBV carriers and explain the complex chromosome changes in HCCs . Mouse array CGH raw data: GEO Accession No. GSE61378 ( http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc= GSE61378 ) Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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